1. Field of the Invention
The present invention relates to a liquid-droplet jetting apparatus which jets liquid droplets, and a liquid transporting apparatus which transports a liquid.
2. Description of the Related Art
As an ink-jet head which jets liquid droplets from a nozzle, ink-jet heads having various structures have been hitherto known. For example, U.S. Pat. No. 6,969,158 discloses an ink-jet head which includes a channel unit provided with a plurality of pressure chambers which are arranged along a plane and which communicate with a plurality of nozzles, respectively; and a piezoelectric actuator which selectively applies a pressure to an ink in the pressure chambers.
The channel unit has a structure in which a plurality of plates including a cavity plate in which the pressure chambers are formed, and a manifold plate in which a manifold communicating commonly with the pressure chambers are stacked; and in which the pressure chambers are arranged to be disposed above the manifold and to overlap partially with the manifold in a plan view.
The piezoelectric actuator includes a plurality of piezoelectric layers (piezoelectric sheets) arranged continuously on an upper surface of the cavity plate so as to cover the pressure chambers; a plurality of individual electrodes arranged on an upper surface of a piezoelectric layer disposed uppermost in the piezoelectric layers, so as to face the pressure chambers respectively; and a common electrode which faces the individual electrodes, respectively, sandwiching the uppermost piezoelectric layer between the common electrode and the individual electrodes. Further, a plurality of contact points (land portions) are drawn from the individual electrodes respectively, and contact points of a flexible printed circuit (FPC) are electrically connected to the contact points of the individual electrodes respectively. Furthermore, when a drive voltage is applied via the FPC, to a certain individual electrode of the individual electrodes, from a driver IC which is a driving circuit, an electric field is generated in a portion of the piezoelectric layer between this individual electrode and the common electrode, thereby deforming the piezoelectric layer. With the deformation of the piezoelectric layer, a volume of a pressure chamber, included in the pressure chambers and facing the individual electrode to which the drive voltage was supplied, is changed, thereby applying a pressure to the ink in the pressure chamber.
Upon connecting the FPC to the piezoelectric actuator, the piezoelectric actuator and the FPC are joined by a solder or the like, while pressing the FPC against the contact point of the piezoelectric actuator. At this time, when rigidity (stiffness) of an area of the piezoelectric actuator at which the contact points are arranged is low, the FPC cannot be pressed sufficiently against the contact points, thereby lowering a reliability of electrical connection between the piezoelectric actuator and the FPC. In view of this, in the ink-jet head described in U.S. Pat. No. 6,969,158, each of the contact points on the upper surface of the piezoelectric layer is drawn from one of the individual electrodes, formed on the upper surface of the piezoelectric layer at an area facing one of the pressure chambers which is a cavity, up to another area having high rigidity (area facing one of partition walls separating the pressure chambers) and not facing the pressure chamber.
In the above-mentioned ink-jet head described in the U.S. Pat. No. 6,969,158, positions of the pressure chambers and the manifold are different in view of the vertical positional relationship. Therefore, a communicating channel communicating each of the pressure chambers and the manifold is required to be formed such that the communicating channel is extended in a direction of thickness of the channel unit, and thus a shape of the ink channel becomes complicated. Further, since it is necessary to stack a plate additionally for forming the communicating channel extended in the direction of thickness, thus increasing the number of plates.